1. Field of the Invention
The invention relates to a single-layer or multi-layer plastic skin as a surface covering for coated objects. Similarly, particularly suitable methods for producing such a plastic skin are disclosed, and also a trim part coated with such a plastic skin for the passenger compartment of a motor vehicle.
Grained, patterned or finely structured plastic skins forming surfaces for objects are also known and are used for example for the interior trim in vehicles, often in the form of relatively soft, underfoamed films with a pleasing feel, for instance for the trim of dashboards or the inner shells of doors, etc. With appropriate adaptation in terms of strength and design, such films are of course also used for other articles that are provided with a high-quality coating.
There are various methods known in the prior art for producing such plastic skins, for example rolling and/or embossing methods for producing “endless” film webs of thermoplastic material, or methods for producing individual ready-from-the-mold molded skins, that is to say plastic moldings.
In the case of the rolling and embossing methods, an embossing roller is used to provide a thermoplastic film in the form of a web with a three-dimensionally structured, embossed surface, that is to say for instance a grained “leather surface.”
Ready-from-the-mold molded skins in this context refer to more or less rigid plastic moldings that are produced in molds by various sintering or spraying processes, for example, and in the case of which one or more liquid or powdered components are introduced into a mold and react/cure there. Ready-from-the-mold molded skins are consequently also created by rotational sintering, for example by methods for producing so-called slush skins.
In the case of these ready-from-the-mold methods there is also the possibility of fixing the surface structure/texture, i.e. the surface of the plastic skin, that is to say for instance the appearance of a grain effect, and the geometry of the entire component in a single molding process during production. For this purpose, for example, the grained structure and component geometry are introduced as a negative into a mold, the plastic skin is shaped by sintering or spraying processes and then the said skin is removed.
Both the web material and the molded skins are generally provided on the rear side with a layer of plastic foam, either after the embossing and/or after bringing and thermoforming them into the component mold (web material) or already in the mold in which the plastic skin was produced (molded skin). Of course, other methods of foam coating, such as for instance brushing methods, are known. By this subsequent “foam backing,” an already quite rigid three-dimensionally shaped component is obtained. Foam backing here represents only one possible way of forming a support structure for the plastic skin. Also known for instance is the adhesive attachment of supporting structural elements made of hard plastic.
European published patent application EP 1 190 828 A1 and its counterpart U.S. Pat. No. 7,192,543 B2 describe a method for producing ready-from-the-mold melted/molded articles, such as for instance dashboards, door panels or glove compartments, in which a divided lower mold is first, and at least partially, lined with a flexible film, which covers over the seams that are present in the mold, and which has on its inner side a grain effect, for example a leather texture. A reactive mixture is sprayed onto the flexible film and then forms the outer skin of the component, before further reinforcements or layers of foam are applied by various spraying or melting-molding methods.
After the production process, the molded skins with the support structure are usually given a clean finish, i.e. any edges of skin there may be are cut off and, in the case of dashboards, for example, the necessary clearances or holes for instruments, switches, decorative strips, radios, etc. are produced. After that, for example, all the switches and signaling elements are individually fitted into the dashboard and wired or provided with connecting lines, which can then be connected when they are installed in the vehicle. The same applies to the installation of instruments, lighting means, loudspeakers, and the like. Decorative strips and mountings must likewise also be attached.
Altogether, therefore, considerable effort, a series of time-consuming and cost-intensive production steps and logistical planning are still required before a ready-to-install dashboard, a door insert or similar components with functional elements are passed on to the plant carrying out further processing, here that is to the vehicle manufacturer.